The ubiquitous nature of mobile networks makes their reliability crucial as society grows increasingly dependent on the mobile service provided to billions of users. While the service provided by mobile networks may be used for private communication purposes, other purposes such as, business, health, education, and the like may also rely on the constant connectivity offered by mobile networks. Accordingly, it may be a jarring experience for businesses and individuals if they lose connectivity to a mobile service.
In a typical cellular radio system (e.g., a mobile network), wireless terminals (also known as mobile stations and/or user equipment units (UEs)) communicate via a radio access network (RAN) to one or more core networks. The RAN covers a geographical area which is divided into cell areas, with each cell area being served by a base station, e.g., a radio base station (RBS), which in some networks may also be called, for example, a “NodeB” (UMTS) or “eNodeB” (LTE). A cell is a geographical area where radio coverage is provided by the radio base station equipment at a base station site. Each cell is identified by an identity within the local radio area, which is broadcast in the cell. The base stations communicate over the air on radio frequencies with the UEs within range of the base stations.
In some versions of a radio access network, several base stations are typically connected (e.g., by landlines or microwave) to a controller node (such as a radio network controller (RNC) or a base station controller (BSC)) which supervises and coordinates various activities of the plural base stations connected thereto. The radio network controllers are typically connected to one or more core networks.
Typically mobile networks are designed with some degree of redundancy. For example, the loss of one base station might not affect the overall service provided by a network. However, more pervasive failures caused by human error, natural disasters (e.g., a tsunami), or man-made disasters (e.g., a military conflict) may happen. In such instances the loss of network resources may impact the service provided to UEs. The loss of network resources and mobile service may be more pronounced in an emergency situation (e.g., a natural disaster) where such mobile service may play a vital role for emergency personnel.
In certain instances, there may be multiple mobile networks in a particular geographic location. A first mobile network may fail in the location, but other mobile networks may still be operational at the same location. Yet, subscribed UEs of the affected mobile network may not be able to obtain service from the other mobile networks to which they do not subscribe.
As an example, in 2005, hurricane “Gudrun” in southern Sweden brought down multiple base stations. The inoperability of certain base stations caused service disruptions for some users. However, while base stations for certain mobile operations were inoperable in certain areas, in many areas, at least one mobile network operator had an operable base station. Accordingly, even though there may have been an operable base station (with an associated mobile network operator) within range of an otherwise “stranded” mobile subscriber, the subscriber may not have been able get service from that mobile network operator.
One reason “stranded” mobile subscribers may not obtain service from other mobile network operators is a lack of national roaming agreements between mobile operators. National roaming agreements may allow users to roam between different operators in the same country. However, in practice certain mobile operators may be reluctant to make such national roaming agreements due to business reasons. For example, mobile network operators may choose to compete on the quality of coverage they provide in a given country.
Where there are no national roaming agreements, one possible workaround might be to use a SIM card from another country. An international roamer could select any of the local networks whenever at least one is available. However, the option of using an international SIM card may not be available for every mobile subscriber. Moreover, such a solution may not work for local inhabitants affected by a hurricane who may need immediate communications service.
Accordingly, some level of cooperation among mobile network operators may be needed. Indeed there may be reasons for mobile operators to cooperate in such emergency situations. First, government entities may provide incentives for cooperation. Second, outages in coverage may affect the economic viability of a company that runs a mobile network. Third, cooperation among operators may decrease the overall cost of providing high reliability mobile service for subscribers. Mobile network operators may realize that multiple networks on essentially the same national coverage area can provide inherent reliability for network failures. Conversely, achieving the same level of reliability within a single mobile network may require an extreme degree of redundancy with a correspondingly high price tag. Accordingly, the aggregate reliability of national mobile operators may provide an economic justification for the operators to cooperate.
Cooperation between national mobile operators may take various forms. One approach may be an emergency-only national roaming agreement, (e.g., one that is only invoked when there is some substantial network failure). However, such an approach may be possible only if the necessary business and legal agreements have been made ahead of time. Further, there may be additional problems with such a solution.
First, the UEs may be configured in such a way that the other networks are marked as forbidden such that the UE may not select other networks independent of any prior standard roaming agreements. Second, reprogramming UEs (e.g., by redefining a forbidden public land mobile network (PLMN) list, or using a steering of roaming feature to direct the terminal to (or away from) a specific PLMN) on the fly during an emergency situation may not be viable because: 1) a mass reconfiguration of all connected UEs may further congest the mobile network; and 2) the UEs not connected (and thus in need of connectivity the most) may not receive the reconfiguration instructions.
It will be appreciated that emergency calling (e.g., 911) may ignore even forbidden networks. However, emergency calling may be only a very limited service. Disconnected users may want to have all the communication services provided by their normal service (e.g., to call families, access the internet, get the latest news, etc). Furthermore, usage of emergency call services may present a new problem if people in a disaster area can only access emergency numbers. This may lead to people calling the emergency number for non-emergency situations (e.g., to get information, etc). Accordingly, this may increase the call burden to emergency call centers during a situation such as hurricane Gudrun.
Thus, it will be appreciated that the current methods are not sufficient. Accordingly, it would be desirable to provide a method and/or system of increasing mobile network reliability.